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Sass Theme Api Middleware

This express middleware allows you to create an api that returns dynamic and custom css based on the url of the request and Sass stylesheets. Variables are included in the url, e.g.

/urlBase/primaryColor/blue/secondaryColor/red will pass the following sass to node-sass:

$primaryColor: red;
$secondaryColor: blue;


This middleware must be placed upstream from your static middleware. This is to allow the middleware to check if the sass needs to be recompiled.


  • urlBase : string, to remove from beginning of url path that is not a var/value pair
  • publicDir : string, absolute path to public dir where compiled css is to be stored
  • includePaths : array of strings, absolute paths of where sass imports will look
  • outputStyle : string, passed directly to node-sass, see node-sass for available options
  • beforeUrlVars : function(queryParams) callback function that is passed the url query parameters that should return a string to be added to sass before url vars, e.g. default palette import
  • afterUrlVars : function(filename) callback function that is passed the filename of the css file requested in the url that should return a string to be added to sass after url vars, e.g. main import


Heavily inspired by node-sass-middleware